Coil assembly



June 22, 1965 s, A. ADAMS ETAL COIL ASSEMBLY 2 Sheets-Sheet 1 Filed Sept. 12. 1961 l I 1 1|!llllllllll Sfan/ey A. Adams Dona/d Hubert I INVENTORS.

June 1965 s. A. ADAMS ETAL COIL ASSEMBLY Filed Sept. 12, 1961 2 Sheets-Sheet 2 l6 26 35 $4 F/ ,2 I

g I 5 20 4' I E t i E 32 i I I ,48 5 I4 I Q 34 44 i I Q Stanley A. Adams Dona/d Hubert 1N VE N TORS,

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United States Patent O 3,191,131 COIL ASSEMBLY Stanley A. Adams, South Haven, and Donald Hubert, Kalamazoo, Mich, assignors to Adams Electronics, Inc., Bangor, Mich., a corporation of Michigan Filed Sept. 12, 1961, Ser. No. 137,653 6 Claims. (Cl. 33376) The present invention generally relates to an improved and novel coil assembly of the type having a core having a threaded engagement with the coil form together with l a novel coil form having longitudinally arranged serrations on the exterior surface thereof upon which a coil may be wound thereby preventing the coil windings from sliding on the form.

Another very important feature of the present invention is to provide a coil assembly having a novel contact arrangement by virtue of U-shaped lugs which interlock around an insulated eyelet thereby providing positive contact at the point of compression formed by the eyelets thereby providing a much better contact arrangement and also eliminating the danger of shorted capacitors due to the insulated eyelet which protrudes below the bottom of the coil form base.

The present invention represents an improvement over that structure disclosed in copending applications Serial No. 23,545, filedi April 20, 1960 for Coil Assembly With Threaded Steam Core, now Patent No. 3,155,895, issued November 3, 1964,-and Serial No. 85,822, filed January 30, .1961 for Double Coil Assembly now abandoned,

A very important object of the present invention is to provide. a coil assembly having a novel one-piece coil form including an adjoining base which prevents the coil form from turning in the coil assembly.

Another very important object of the present invention is the provision of a coil form constructed of plastic material such as nylon or the like having two cores disposed ihteriorly of the coil form and movable in relation to a pair of coil windings on the coil form. The interior of the coil form is provided with six rigid triangular ribs which allow the cores to be threaded through the core and cut through the apex of the triangular ribs for retaining the cores in adjusted position thereby avoiding any shift in the core after it has been set. Also, this cut through feature of the threads on the core in relation to the triangular ribs is concerned, this will prevent any rotational shifting of the coil or any component thereof due to the push through of the threads.

A most important feature of the present invention is the provision of serrations on the exterior-surface of the coil form on which the windings are disposed thus preventing any relative sliding movement between the windings and the coil form. The serrations are arranged in a plurality of circumferentially spaced longitudinal rows and are relatively small but are sufiicient to anchor the coil windings in place. This feature is quite important since placement of two windings and the mutual inductance is held constant without thenecessity of cementing the windings to the coil form.

Still another very important feature of the present invention is the particular construction of the contact members and their relationship to the capacitor assembly in which the coil form base is provided with insulated eyelets which surround the retaining metallic grommets and the contact elements have U-shaped lugs on the inner end thereof receiving the insulated eyelet thus associating the contact surfaces closely adjacent the grommet and insulated eyelet which actually forms the compression pressure thereby assuring that proper contact will be made since the contacts are located directly in or under the pressure exerted by the grommets. Also, the insulated eyelets completely preclude any danger from shorting of "ice the capacitor which sometimes is due to movement of the contact lug into engagement with the grommet or into engagement with each other and this shifting of the contact lugs is prevented by the U-shaped configuration on the inner end thereof which prevents any shifting of the lug whatsoever.

As in the previously disclosed devices mentioned in the copending applications, the present invention is especially useful with high frequency inductance assemblies in the form of transformers and the like employing windings that are tuned by varying the position of a ferrous core with respect to the windings. shielding can and applicants particular assembly includes a novel arrangement for the shielding can in which it is employed for retaining the capacitorcomponents in assembled compressed relation. Also, since two cores are used, the base of the coil form and the components of the capacitor have an aperture receiving a suitable instrument for rotating the core thus adjusting the longitudinal position thereof.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective view of the coil assembly of the present invention;

FIGURE 2 is a longitudinal, vertical sectional view of the coil assembly with the coil form, coil windings and capacitor shown in elevation;

FIGURE 3 is a bottom plan view of the coil assembly;

FIGURE 5 is a transverse, plan sectional view taken substantially upon a plane passing along section line 5-5 of FIGURE 4 illustrating the construction of the coil form and the relationship of the core to the. ribs in the coil form;

FIGURE 6 is a transverse, sectional View taken substantially upon a plane passing along section line 6-6 of FIGURE 4 illustrating the construction of the capacitor and illustrating the relationship of the U-shaped contact lugs to the insulated eyelets and the grommets disposed in the eyelets;

FIGURE 7 is a top perspective view of the coil form illustrating the one-piece unitary construction thereof;

FIGURE 8 is a partial bottom perspective view of the coil form illustrating the construction of the base and the insulated eyelets integral therewith; and

FIGURE 9 is a perspective view of one of the contact members employed in the present invention illustrating the U-shaped configuration of the inwardly extending lug thereon.

Referring now specifically to the drawings, the numeral 10 generally designates the coil assembly of the present invention which may be employed for any number of different uses including those in which tuned coil assemblies are normally employed. The coil assembly 10 includes a shielding can 12 having peripheral side walls 14, an upper end wall 16 and with the lower end thereof being open. The upper end wall 16 is provided with an opening 18 for permitting access into the interior thereof. The shielding can 12 is preferably square or rectangular in configuration.

and may be constructed of metal or some other conductive material and an insulating sleeve 20 is disposed in-' Such devices include a bly generally designated 'by numeral 22 and a capacitor assembly generally designated by numeral 24'.

The coil assembly includes an elongated tubular coil form 26 having a generally fiat and square or rectangular base 28 integral therewith in that the base and the coil form are of one-piece construction of insulating material such as plastic. A suitable plastic has been found to be nylon which readily lends itself to standard manufacturing procedures.

The exterior surface of the coil form 26 is provided with a plurality of longitudinal rows of relatively small projections or serrations 38 on which a pair of coil winding assemblies 32 and 34 are disposed. The assemblies 32 and 34 are spaced longitudinally from each other and the serrations enable the windings to be disposed on the form without the necessity of cementing and will in elfect retain the mutual inductance at a desired constant.

Disposed interiorly of the coil form 26 is a pair of longitudinally movable cores 36 and 38 which are externally threaded as at 40 and which have a polygonal bore 4-2 extending therethrough for receiving a suitable instrument for rotation therof such as a polygonal wrench or tool generally known as an Allen Wrench. The cores are hollow for the purposes of air circulation and for receiv-' ing an implement or tool but the cores could also have a other suitable structures for receiving a rotating implement such as a screwdriver or the like. Each of the cores 36 is constructed of a magnetic substance such as compressed powdered ferrite, powdered iron having low permeability or any suitable equivalent material. The cores are disposed completely within the coil form and access to the core 36 may be had through the opening 18 and the open upper end of the coil form 26 which abuts the interior surface of the opening 18 as illustrated in FIG: URE 2. Access to the lower or inner core 38 is gained through an opening 44 in the base 28 and also an opening extending through the capacitor 24 in a manner described hereinafter.

The tubular coil form 26 which is constructed of plastic material such as nylon has a plurality of radially inwardly projecting triangular ribs 46 which extend substantially throughout the length of the coil form. The ribs 46 are of equilateral triangular construction and are equally spaced circumferentially of the coil form. The

threads 40 on the cores 36 and 38 actually out through or find their way through the apex of the triangular ribs 46 thus eliminating any tendency of the core to shift the coil form and also providing a means for retaining the cores in rotatable adjusted position in relation to the winding assemblies 32 and 34.

The triangular ribs provide a point or apex which allows the edge of the threads on the cores to engage itself gradually into the stationary rib which does not flex circumferentially with the rotation of the core in either direction. The base of the triangle or the area approaching the base increases in width thus furnishing the core with sufiicient push through resistance to met the specifications that are generally required of this type of unit. 7

The coil winding assemblies 32 and 34 are provided with leads 48 which extend downwardly through notches 50 in opposed edges of the coil form base 28. Each of the notches 50 is generally T-shaped in configuration with the transverse portion of the T-shaped notch being disposed inwardly and the T-shaped portions of the notches receive the leads 48 as they pass therethrough for connection with the capacitor assembly 24. Also, the base 28 is provided with a pair of integral depending eyelets or sleeves 52 which are hollow and which are in alignment with openings 54 in the base 28. The insulating "eyelets 52 are of integral one-piece unitary construction with the base 28 and the coil form 26 thus providing a one-piece structure as far as the coil form 26, base 23 and eyelets 52 are concerned.

The capacitor assembly 24 includes a lower or bottom insulation panel 56 of substantially the same size as the base 28 and disposed in spaced parallel relation thereto.

, such as by soldering or the like.

The insulating panel 56 is provided with T-shaped notches 58 in the side edges thereof in alignment with the notches 50 in the base 28. Also, the panel 56 is provided with a central opening at) in alignment with the opening 44 for providing access into the interior of the coil form 26 and there is also provided a pair of small openings therein designated by numeral 52 which are in alignment with the openings 54 and which receive the lower ends of the insulating eyelets 52 when in assembled relation as illustrated in FIGURE 4.

Disposed between the base 28 and the insulating panel 56 is an insulating sheet of material 64 and a sheet of material 66 of mica or the like having coated areas of .conductive material 68 on both surfaces thereof. Both the sheets or panels 64 and 66 have central openings 70 in alignment with the openings 60 and '44 thus providing access into the interior of the coil form for rotating the inner core 33.

Contact members 72 extend through the transverse portion or" the T-shaped notches 58. There are four contact members 72 which taper downwardly and have a notch adjacent the upper end thereof designated by numeral 74 to which the leads 4-? are attached in a suitable manner The upper end. of each contact 72 is provided with an inwardly extending lug 76 having a U-shaped terminal end portion 78 defining a notch or slot 8d. The U-shaped end portion 78 may be considered to be bifurcated for straddling the insulating eyelet 52 when assembled therewith. The lugs 7 6 extend on opposite sides of the sheet 66 with the lugs which partially overlap each other being disposed on opposite sides of the sheet 66 for engagement with the conductive coated areas thereon.

'For retaining the capacitor assembled, there is provided a pair of grommets 82 of metallic construction" end portion 78 straddling the insulating eyelet 52 will assure that proper contact is obtained at all times since the U-shaped portion is disposed at the point of greatest compression thus assuring that the contacts are at the point of greatest compression. Also, the insulating eyelets 52 prevent lateral movement of the lugs 76 and also eliminate any contact'of the lugs 76 with the metallic grommets and thus reducing the danger of shorting of the capacitor due to the fact that the lugs are looked as far as lateral movement is concerned and insulated from the grommet which is of a metallic construction and which could possibly short the capacitor.

The present invention may be incorporated into various types of coils such as those used for insertion into printed circuit boards and other types used in metal chassis and both arrangements employ the same basic features described hereinabove.

The shielding can 12 is provided with a depending mounting lug 82 which is received in a longitudinal recess 84 in the bottom edge portion of the can. The lug 82 is provided with a pair of outwardly struck lugs 86 in serted through slit-like openings 83 in the shielding can and are then deformed upwardlyand downwardly respectively for rigidly securing the lugs 82 in place. Also, the shielding can is provided with inwardly struck projections which underlie the lower insulating panel 56 for retaining the entire assembly within the confines of the shielding can. It is pointed out that the opening 18 closely engages and prevents upward movement of the coil form 26 thus securely locking the inserted assembly between the top wall 16 and the inwardly struck lugs 90 for retaining the device in assembled condition.

The foregoing is considered as illustrative only of the 5 principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. In a coil assembly, an elongated tubular coil form for receiving a winding thereon, a base integral with said coil form and being of one-piece construction therewith, capacitor means mounted below said base, contact elements connected with the winding and capacitor means, a movable core inserted into the end of the coil form and in threaded engagement therewith, wherein said coil form and base being constructed of plastic material, said coil form being hollow and provided with a plurality of inwardly extending ribs of triangular cross-sectional configuration on the inner surface thereof, said core being externally threaded whereby the threads on the core will cut through the apex of the triangular ribs thus retaining the cores in rotatable adjustable position.

2. The structure as defined in claim '1 wherein the external surface of said coil form is provided with a plurality of radially extending and longitudinally spaced projections on which the winding is mounted thereby retaining the winding in position without requiring cement.

3. In a coil assembly, an elongated tubular coil form for receiving a winding thereon, a base integral with said coil form and being of one-piece construction therewith,

capacitor means mounted below said base, contact elements connected with the winding and capacitor means, a movable core inserted into the end of the coil form and in threaded engagement therewith, wherein said capacitor means including sandwiched insulated sheets with at least one of said sheets having silvered surface areas thereon, said insulated sheets including a bottom member, grommets extending through the sheets, the base and the bottom for retaining the capacitor means assembled, insulating sleeves integral with said base extending in enclosed relation to the grommets thus insulating the grommets from the sheets.

4. The combination of claim 3 wherein said contact elements each includes an inwardly extending lug terminating in a bifurcated U-shaped end portion, each U- shaped end portion straddling an insulating sleeve thereby preventing shifting of the contact elements and insulating the contact elements from the grommets.

5. in a coil assembly, a one-piece coil form and base plate constructed of plastic material, said base plate having depending sleeves unitary therewith for encircling assembling grommets and receiving U-shaped ends of contact members, the exterior surface of said coil form having serrations thereon for locking a coil winding in place, said coil form also being provided with radially inwardly extending ribs on the inner surface thereof of equilateral triangular configuration for engagement by a threaded core.

6. In a coil assembly, an elongated tubular coil form for receiving windings thereon, a base integral with said coil form and being of one-piece construction therewith, capacitor means mounted below said base, contact elements connected with the windings and capacitor means, a movable core inserted into the ends of the coil form in threaded engagement therewith, and the external surface of said coil form being provided with a plurality of radially extending and longitudinally spaced projections on which the windings are mounted for retaining the windings in position without requiring cement whereby the mutual inductance of said windings is maintained constant.

References Cited by the Examiner UNITED STATES PATENTS 1,887,470 11/32 Twort 336207 2,283,924 5/42 Harvey 333--78 2,544,508 3/51 Mackey 336-436 2,547,085 4/51 Mazzola 323--76 X 2,631,192 3/53 Wallin 33378 2,648,031 8/53 Lang 333--78 2,972,713 2/61 Sutton 32376 X HERMAN KARL SAALBACH, Primary Examiner. ROBERT C. SIMS, Examiner. 

1. IN A COIL ASSEMBLY, AN ELONGATED TUBULAR COIL FORM FOR RECEIVING A WINDING THEREON, A BASE INTEGRAL WITH SAID COIL FORM AND BEING OF ONE-PIECE CONSTRUCTION THEREWITH, CAPACITOR MEANS MOUNTED BELOW SAID BASE, CONTACT ELEMENTS CONNECTED WITH THE WINDING AND CAPACITOR MEANS A MOVABLE CORE INSERTED INTO THE END OF THE COIL FORM AND IN THREADED ENGAGEMENT THEREWITH, WHEREIN SAID COIL FORM AND BASE BEING CONSTRUCTED OF PLASTIC MATERIAL, SAID COIL FORM BEING HOLLOW AND PROVIDED WITH A PLURALITY OF INWARDLY EXTENDING RIBS OF TRIANGULAR CROSS-SECTIONAL CONFIGURATION ON THE INNER SURFACE THEREOF, SAID CORE BEING EXTERNALLY THREADED WHEREBY THE THREADS ON THE CORE WILL CUT THROUGH THE APEX OF THE TRIANGULAR RIBS THUS RETAINING THE CORES IN ROTATABLE ADJUSTABLE POSITION. 